Connolly is the figure in whom revolutionary syndicalism and anti-colonial nationalism are held together, and the one who put the combination to the test.
Born in Edinburgh to Irish parents and largely self-taught, he organized in Ireland, Scotland and the United States, where he worked with the Industrial Workers of the World and absorbed its case for One Big Union: industrial rather than craft organization, direct action rather than parliamentary representation, and the union as the structure that would run production after capitalism.
His distinctive argument concerns the relation between the national and the social question. Against nationalists who postponed social demands until independence, he insisted that a free Ireland which left landlords and capitalists in place would have changed its flag and nothing else — "England would still rule you through her capitalists". Against socialists who dismissed nationalism as a distraction, he argued that a people held down by an imperial power cannot organize as workers until that grip is broken. Labour in Irish History (1910) reconstructs the Irish past as a record of dispossession in order to make both halves of the case.
He commanded the Irish Citizen Army — formed to defend strikers after the 1913 Dublin lockout — in the Easter Rising of 1916, and was executed by firing squad, tied to a chair because his wounds prevented him standing.
The argument outlived him. Every subsequent movement that has had to decide whether national independence and social transformation are one task or two has been arguing on ground he mapped.